In most electric steam irons of this kind the water supply from the water tank to the evaporation chamber is carried out via a dripfeed valve, which enables the water to flow in a controlled manner into the evaporation chamber. Piston pumps, which may be actuated by buttons projecting from the iron handle DE-OS 24 42 126), are provided for producing a steam jet and for spraying water. The disadvantage in these irons, however, is that the dripfeed valves are very susceptible to calcination which leads to a narrowing of the extremely small water port. The actuation of the piston pumps requires, moreover, additional strength which a woman's hand cannot be expected to have. In order to overcome this disadvantage, it is known in steam irons that the water may be supplied from the water tank into the evaporation chamber via an electrically controlled pump (DE-AS 11 60 399). Steam irons equipped with electrically controlled pumps and provided with an additional spray device are also known (DE-GM 90 00 917). In these irons, the pump is connected to the evaporation chamber and the spray device via a pipe system and valves.
These known steam irons have the disadvantage that after the switching-on of the pump, it takes a certain time for the user to have enough water with the required water pressure and for the actuated pump to operate continuously, so that it is not possible to feed a quantitively regulated amount of water into the evaporation chamber which is required for producing a steam jet.